How to configure FreePBX for OVH’s SIP trunk

I’m still kind of an Asterisk/FreePBX noob so I took me a while to figure out how to configure OVH’s SIP trunk for inbound and outbound calls. I chose OVH since they offer a SIP trunk for €1/mo (depending on your country the price may be higher) which includes free landline calling to 40 countries: Argentina, …